The president is able to check the power of the legislative branch through the use of the presidential veto.
The Missouri Compromise was a strategic solution by Henry Clay to keep the slave and free states equal. It prevented conflict between the north and south as both regions had equal representation in congress regarding state senate votes
Many cities had rioted after the ML King assassination
a country forces its schools to promote official state ideology
I would say the transcontinental railroad....it went from the Mississippi river to the California coast